Dual-feed single-cam compound bow

ABSTRACT

A cam is eccentrically journaled at one end of a compound archery bow and a pulley is journaled at the other end of the bow. A cable passes around the pulley to form a bowstring section and a second cable section, both sections forming a dual feed single cam compound bow. The amount of feed out to both ends of the bowstring is approximately the same. One embodiment of the cam provides a large radius cam groove and a smaller radius cam groove which are designed to synchronize the rate of cable feed out at both ends of the bowstring section during the drawing operation. An anchor cable is provided to tie the two limbs of the bow together during the flexing of the bow.

This application is a continuation of application Ser. No. 08/047481,filed Apr. 19, 1993, now U.S. Pat. No. 5,890,480, which is acontinuation-in-part of application Ser. No. 07/875748, filed Apr. 28,1992, now U.S. Pat. No. 5,368,006.

BACKGROUND OF THE INVENTION

In the past, most compound archery bows have used two cams, respectivelymounted on the limb tips at opposite ends of the bow to provide themeans to store more energy in the draw cycle and to reduce the forcenecessary to hold the bowstring in the full draw position. Examples ofsuch compound bows are disclosed in the following U.S. patents.

U.S. Pat. No. Issued To Date Issued 3,486,495 Allen Jun. 23, 19663,890,951 Jennings, et al. Jun. 24, 1975 4,060,066 Kudlacek Nov. 29,1977 4,079,723 Darlington Mar. 21, 1978 4,112,909 Caldwell Sep. 12, 19784,300,521 Schmidt Nov. 17, 1981

The early compound bows utilized cams consisting of eccentricallymounted circular shaped elements. As the desire for more stored energyand greater arrow velocities developed, special shaped cam elements weredesigned to provide these characteristics. These shaped cam elements,like the circular shaped elements, were mounted on the limb tips. It iswell known in the art that to obtain the best bow performance, the camelements at each end of the bow should be properly synchronized witheach other. Patents disclosing various means to accomplish proper camsynchronization include the following:

U.S. Pat. No. Issued To Date Issued 3,841,295 Hunger Oct. 15, 19743,958,551 Ketchum May 25, 1976 4,103,667 Shepley, Jr. Aug. 1, 19784,178,905 Gromer Dec. 18, 1979

The more modern compound bows have reverted back to the more simplisticdesign of the original U.S. Pat. No. 3,486,495 Allen patent, but therequirement for cam synchronization is still present as noted, forexample, by the teachings of the following patents:

U.S. Pat. No. Issued To Date Issued 4,372,285 Simonds Feb. 8, 19834,440,142 Simonds Apr. 3, 1984 4,909,231 Larson Mar. 20, 1990

It is obvious, of course, that the use of a single cam avoids theproblem of cam synchronization and, in fact, there are single cam bowsknown in the prior art. One such bow, popularly referred to as the“DynaBo” was invented by Len Subber. The original Dynabo design had oneworking limb located at the upper end of the bow handle. A single camelement was mounted on a rigid pylon at the lower end of the bow. Thesingle cam element functioned in the same manner as the cam elements onthe previously mentioned two cam bows. As the Dynabo was drawn, onetrack of the cam element payed out line to the bowstring which was fixedto the upper limb tip and the other track on the cam element acted as atake-up reel for a second line that was also anchored at the tip of theupper working limb.

Since there was only a single cam element, there was not asynchronization problem between two cams. There was, however, a problemis synchronizing the rate that the cam fed out cables to the bowstringat the lower end of the bow and the rate that the flexing of the upperlimb feed out cable to the bowstring at the upper end as the bow wasdrawn. The result was a rather unpleasant feel to the bow as it wasdrawn and there was a drastic movement of the nocking point and the rearend of the arrow as the bow was drawn and released. This, in turn, madeit very difficult to achieve good arrow flight from the bow under normalconditions. An early version of the DynaBo was described in theSeptember 1976 edition of “Archery World” beginning at page 28.

The Dynabo single cam concept was offered in at least three differentversions from as many manufacturers during the 1970's, and at least onemanufacturer, Graham's Custom Bows, employed the Dynabo concept, withtwo working limbs. A description of the Graham bow is contained in theJune/July edition of “Archery World” magazine. The Dynabo bow, however,never did become an acceptable alternative to the two cam bows and, infact, appears to have lost whatever popularity it had achieved by thelate 1970's.

Another known prior art device that had the capability of providing asolution to the previously mentioned problems of cam synchronization andsynchronized box string feed out (the latter being desirable to enablethe nock end of the arrow to travel in a smooth, consistent path upondraw and release of the arrow) is set forth in U.S. Pat. No. 4,562,824issued to Jennings. This patent teaches the use of a single multiplegrooved cam mounted on a pylon attached to the bow handle. The cam hadone string track feeding cable attached to an idler pulley mounted inthe limb tip at one end of the bow and a second track feeding line to asecond idler pulley mounted in the second limb tip at the other end ofthe bow. The cam also has two additional tracks, each of which aretaking up line while the string tracks are feeding out line to the bowstring. One take-up track is taking up a line which is anchored at onelimb tip while the other take-up track is taking up a line which isanchored at the opposite limb tip. Thus, the '824 patent teaches ahighly complicated system, as compared to the present invention, that iscomposed of considerably more parts resulting in a compound bow havinggreater mass weight than the more conventional two cam compound bow.

A single cam bow developed by Larry D. Miller in the late 1970's orearly 1980's was the subject of a U.S. patent application titled“Archery Bow Assembly” (hereinafter referred to as the “Millerapplication”). The Miller application discloses the use of a singlepulley, having two grooves thereon for feeding out line to the bowstring. The primary groove is circular and concentric with the axle ofthe circular pulley. The secondary groove, also circular, may beslightly eccentric for the purpose of maintaining the nocking point ofthe bowstring perpendicular to the handle section of the bow. A thirdeccentric groove carries a take-up cable to provide the entire means ofcompounding (i.e. achieving the desired reduction in holding weight atfull draw and storage of energy).

The Miller application, the serial number of which is not known, may beconsidered material to the examination of the subject application.

SUMMARY OF THE INVENTION

The present invention embodies a simple, lightweight compound bowconstruction which solves the cam synchronization problem of two cambows and overcomes the problems of synchronously feeding out cable tothe upper and lower ends of the bowstring. The resulting bow has asmooth, desirable mocking point travel path which enables ease inmatching arrows to the bow and provides consistency in performance.

A cam is eccentrically journaled at one limb end of the bow and a pulleyis journaled at the other limb end of the bow. A cable passes around thepulley to form a bowstring section and a second cable section, bothsections forming a dual feed single cam compound bow. The amount of feedout to both ends of the bowstring is approximately the same. Oneembodiment of the drop-off cam provides a large periphery cam groove anda smaller periphery cam groove which are designed to synchronize therate of cable feed-out at both ends of the bowstring section during thedrawing operation. Other embodiments of the invention are alsodisclosed.

An anchor cable is provided to tie the two limbs of the bow togetherduring the flexing of the bow. The anchor cable may be fixed at one endto the axle of the concentric pulley and at the other end fixed in agroove in the cam to synchronize the flexing action of the bow limbs.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view showing one embodiment of theinvention;

FIG. 2 is a side elevational view of the cam shown in FIG. 1;

FIG. 3 is the opposite side elevational view of the cam shown in FIG. 2;

FIG. 4 is a top plan view of the cam taken along line 4—4 of FIG. 3;

FIG. 5 is a rear elevational view of the upper limb tip portion of thearchery bow of the present invention showing the anchor cable mountingon the concentric pulley axle;

FIG. 6 is a view of the unassembled anchor cable of the presentinvention;

FIG. 7 is a side elevational view, similar to the view, shown in FIG. 2,and showing an alternative embodiment of the cam of the presentinvention;

FIG. 8 is a side elevational view, similar to the view shown in FIG. 2,and showing another embodiment of the cam of the present invention;

FIG. 9 is a side elevational view, similar to the view shown in FIG. 2,and showing a still further embodiment of the cam of the presentinvention;

FIG. 10 is the opposite side elevational view of the cam shown in FIG.9;

FIG. 11 is a top plan view taken along line 11—11 of the cam shown inFIG. 10;

FIG. 12 is a side elevational view similar to the view shown in FIG. 2,and showing a still further embodiment of the cam of the presentinvention;

FIG. 13 is the opposite side elevational view of the cam shown in FIG.12;

FIG. 14 is a top plan view taken along line 14—14 of the cam shown inFIG. 13;

FIG. 15 is a side elevational view similar to the view shown in FIG. 2,and showing a still further embodiment of the cam of the presentinvention;

FIG. 16 is the opposite side elevational view of the cam shown in FIG.15; and

FIG. 17 is a top plan view taken along line 17—17 of the cam shown inFIG. 16.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1 of the accompanying drawings, an archery bow assembly B isillustrated which includes a central handle portion 10, having a pair oflimbs 12 and 14, connected at their inner ends in fixed relation to thehandle portion 10. The limbs 12 and 14 provide the desired resistance tobending which determines the draw weight of the bow and the force withwhich the arrow is discharged.

As shown in FIGS. 1-4, the outer ends of the bow limbs provide wheelreceiving slots which define wheel mounting forks, respectivelydesignated by the numbers 12a and 14a, for mounting axle pins 15 and 16.A pulley 17 is concentrically mounted on the axle pin 15. In this formof the invention, the pulley 17 is provided with a single groove. Asshown in FIGS. 2-4, an eccentric drop-off cam 18 is mounted on axle pin16 and has three eccentrically oriented grooves, 18a, 18b, and 18cformed in the outer periphery thereof to provide three separate cablegroove paths.

A cable 22 has a medial portion trained around concentric pulley wheel17 to form a main cable section or bowstring 22a and a secondary orreturn section 22b, both of which extend across the bow and terminate atthe cam 18. The ends 22c and 22d of the two sections 22a and 22b arerespectively received in grooves 18b and 18c of the cam 18. The end 22cand 22d of the sections 22a and 22b are anchored to the cam 18 as by thecable anchor pins 19a and 19b fixed in said cam 18, as best shown inFIG. 3. In the form shown, three anchor pins 19a are provided to permitadjustment of the effective length of cable 22 and bowstring 22a.

An anchor cable 25 is anchored at one end 25a to the axle 15 (see FIGS.5 and 6) by loops 31 on sections 31a of anchor cable 25 encircling axle15. It is seen that loops 31 extend on both sides of pulley 17 toprovide load balancing and thus prevent twisting of upper limb 12. Theother end of anchor cable 25 (as best shown in FIG. 2) passes around thecam groove 18a on the take-up side of the cam 18 and has a loop 33thereon which is attached to anchor pin 19c and positively ties the endsof the bow limbs 12 and 14 together to form a direct connection betweenthe limbs 12 and 14.

The operation of the archery bow having the eccentric cam illustrated inFIGS. 1-4 will next be described. When the archer draws the bowstring22a, cam 18 is caused to rotate in the counterclockwise direction asviewed in FIG. 2 and bowstring 22a is fed out from cam 18 in thedirection of the generally vertical arrow adjacent bowstring 22a in FIG.1. Counterclockwise rotation of cam 18 likewise causes return section22b to be fed out from cam 18 in the direction toward pulley 17. Returnsection 22b moves upwardly to the take-up side of concentric pulley 17,around and past the pulley 17 to become the second feed-out portion 22aof bowstring 22. At the same time that the bowstring section 22a is fedout, counterclockwise rotation of cam 18 causes anchor cable 25 to betaken up in groove 18a of cam 18 to cause the synchronized flexing ofthe bow limbs 12 and 14.

Alternative forms of the invention are illustrated in FIGS. 7 and 8, butin each case the dual-feed-out cable sections 22a and 22b operate andextend outwardly from a drop-off cam unit mounted on the limb 14 of thebow in the same manner, as described for the embodiment shown in FIGS.1-4. In the FIG. 7 embodiment, an eccentric drop-off cam 27 isillustrated having the feed-out cable sections 22a and 22b extendingoutwardly therefrom toward the concentric pulley 17. The cam 27 has asingle groove 27b extending all around its complete periphery with thecable sections 22a and 22b received in the groove 27b. The ends of thecable sections are anchored to an anchor pin 27a fixed to one side ofthe cam 27. The anchor cable 25 is also received in groove 27b andsecurely anchored to the anchor pin 27a, as shown in FIG. 7.

Another alternative form of the cam is illustrated in FIG. 8 whichembodies eccentric drop-off cam 28 having a groove 28b thereon whereincable sections 22a and 22b are received. A suitable anchor pin 28a isprovided on the back side of the cam 28 as shown by dotted lines in FIG.8 and both ends of cable sections 22a and 22b are secured thereto in thesame manner as previously described. The anchor cable 25 is trained ingroove 29 of cam 28 and secured to the anchor pin 29a of cam 28 as shownin FIG. 8. Cam 28 is eccentrically mounted on axle pin 16 connected tothe limb 14 of the bow.

The embodiment of the cam shown in FIGS. 9 to 11 also operates in themanner as the eccentric cam illustrated in FIGS. 1 to 4. In thisembodiment, the eccentric drop-off cam 30 has the feed out sections 22aand 22b extending outwardly therefrom toward the concentric pulley 17(not shown). Feed out section 22a is received in a first groove 32 ofcam 30 and feed out section 22b is received in a second groove 34 ofsmaller periphery of cam 30 which is located on one side of groove 32 ofcam 30. Anchor cable 25, as best seen in FIGS. 9 and 11, is located ingroove 36 of cam 30, which also is located on the side opposite ofgroove 32 from groove 34 of cam 30.

Feed out section 22a, as best seen in FIG. 10, may be attached to eitheranchor pin 37 (as shown) or anchor pin 38 on cam 30, and in this mannerthe effective length of feed out section 22a may be adjusted to changedraw length. Feed out section 22b, also as best seen in FIG. 10, isattached to anchor pin 40 on cam 30. Anchor cable 25, as best seen inFIG. 9, is attached to anchor pin 42 which is located on the side of cam30 opposite anchor pins 36, 38 and 40. As in the other embodiments, cam30 is eccentrically mounted on the axle pin 16 connected to the limb 14of the bow.

The embodiment of the cam shown in FIGS. 12 to 14 likewise operates inthe manner as the eccentric cam illustrated in FIGS. 1 to 4. In thisembodiment, the eccentric drop off cam 44 has the feed out sections 22aand 22b extending outwardly therefrom toward the concentric pulley 17(not shown). Feed out section 22a is received in a first groove 46 ofcam 44 and feed out section 22b is received in a second groove 48 ofsmaller periphery of cam 44 which is located outwardly of the centerline of grooves 46 of cam 44. Anchor cable 25, as best seen in FIG. 12,is located in groove 50 of cam 44, which also is located outwardly ofthe center line of groove 46 of cam 44.

Feed out section 22a, as best seen in FIG. 13, may be attached to eitheranchor pin 52 (as partially shown) or anchor pin 54 or anchor pin 56 oncam 44 and in this manner the effective length of the feed out section22a may be adjusted. Feed out section 22b, also as best seen in FIG. 13,is attached to anchor pin 58 on cam 44. Anchor cable 25, as best seen inFIG. 12, is attached to anchor pin 60 which is located on the side ofcam 44 opposite anchor pins 52, 54, 56 and 58. As in the otherembodiments, cam 44 is eccentrically mounted on the axle pin 16connected to the limb 14 of the bow.

The embodiment of the cam shown in FIGS. 15 to 17 operates in the manneras the eccentric cam illustrated in FIGS. 1 to 4. In this embodiment,the eccentric drop off cam 68 has the feed out sections 22a and 22bextending outwardly therefrom toward the concentric pulley 17 (notshown). Feed out section 22a is received in a first groove 70 of cam 68and feed.out section 22b is received in a second smaller peripherygroove 72 of cam 68. Anchor cable 25, as best seen in FIG. 16, islocated in groove 74 of cam 68, which is located intermediate of grooves70 and 72 of cam 68.

Feed out section 22a, as best seen in FIG. 15, may be attached to eitheranchor pin 74 (as shown) or anchor pin 76 on cam 68 and in this mannerthe effective length of feed outsection 22a may be adjusted. Feed outsection 22b, as best seen in FIG. 16, is attached to anchor pin 78 oncam 68. Anchor cable 25, also as best seen in FIG. 16, is attached toanchor pin 80 which is located on cam 68. As in the other embodiments,cam 68 is eccentrically mounted on the axle pin 16 connected to the limb14 of the bow.

It has been found that a desirable approach to designing the grooves inthe cam is to initially have the groove which receives bowstring 22a(the “primary groove”) be approximately twice the peripheral size of thegroove which receives the bowstring 22b (the “secondary groove”). Thesize of the primary groove may, for example, be the peripheral size of acam on a standard bow having two independent cams. A starting point forthe design of the groove which receives anchor cable 25 (the “take upgroove”) for use on limbs having relatively low spring rates andrelatively longer limb tip travel may be, for example, to have the sizeand shape of the take up groove be approximately the same size and shapeas the primary groove. If, however, one desires limbs having a higherspring rate and desires to reduce limb tip travel, the take up cam sizewill be smaller than that of the primary feed cam for a given peak drawweight. Conversely, if one desires limbs having a lower spring rate anddesires to increase limb tip travel, the take up cam size would belarger than that of the primary feed cam for a given peak draw weight.The final shape of the take up cam will depend on the energy storagecharacteristics that are desired. Adjustments of the peripheral size andshape will then be made to the secondary groove to assure that thenocking point travels in a smooth path during the draw cycle. To achievethis, the bowstring is drawn at discrete draw length intervals, forexample, at draw length intervals of one inch and at each such intervalthe nocking point position and travel is analyzed and, if required, thesecondary groove is made either peripherally larger or smaller to assurethat the nocking point travels a smooth path between intervals. Bycontinuing this process of modifying the size and shape of the secondarygroove throughout the draw length, the resulting single cam compound bowwill, among other desirable features, be provided with a smooth nockingpoint path of travel. It should be noted that the amount of storedenergy will be directly related to the leverage ratios between theprimary, secondary groove shapes and will depend on the combined effectof the two bowstring let off leverage arms as compared to the leveragearm of the bowstring take up side.

1. A compound archery bow comprising first and second bow limbs attachedto a handle, said bow limbs having axle pins therein and wherein aneccentrically rotatably mounted cam defining a bowstring section cam anda return section cam is mounted on one of said axle pins with said axlepin passing through at least said return section cam, a cable having abowstring section attached to said bowstring section cam and a returnsection attached to said return section cam, a bowstring cable and areturn cable attached to said eccentrically mounted cam, wherebyrotation of the eccentrically rotatably mounted cam by the bowstringcable section causes the bowstring cable section to be let off andwhereby during at least a portion of said cam rotation the return cablesection is also let off.
 2. A compound archery bow asset forth in claim1 and further including an anchor cable attached to the cam and wherebythe rotation of the eccentrically rotatably mounted cam by the bowstringcable section causes the anchor cable to be taken up.
 3. An A compoundarchery bow comprising an eccentrically rotatably mounted cam defining abowstring section cam and a return section cam, said eccentricallyrotatable cam being mounted on a bow limb with an axle passing throughsaid cam, a bowstring cable attached to the cam, a return cable attachedto the cam said cable having a bowstring section attached to saidbowstring section cam and a return section attached to said returnsection cam and means for rotating the cam to cause the bowstring cablesection to be let off and during at least a portion of said cam rotationto cause the return cable section to be let off.
 4. An eccentricallyrotatably mounted cam, bowstring cable and return cable A compoundarchery bow as set forth in claim 3, and further including an anchorcable attached to the cam and whereby the rotation of the cam causes theanchor cable to be taken up.
 5. The compound archery bow of claim 3,wherein said bowstring section cam and said return section cam define alarge periphery cam and a small periphery cam.
 6. The compound bow ofclaim 5, wherein said small periphery cam has an eccentric periphery. 7.The compound bow of claim 6, wherein said large periphery cam has aneccentric periphery.
 8. A compound archery bow comprising first andsecond bow limbs attached to a handle, an eccentrically rotatablymounted cam mounted on one of said bow limbs with an axle passingthrough said cam, an anchor cable attached to an axle mounted in thesecond of said first and second bow limbs, a bowstring cable and areturn cable attached to said eccentrically mounted cam, wherebyrotation of the eccentrically rotatably mounted cam by the bowstringcable causes the bowstring cable to be let off and the anchor cable tobe taken up, and, whereby during at least a portion of said cam rotationthe return cable is also let off.
 9. A compound archery bow as set forthin claim 8, wherein the first and second bow limbs each have a mountingfork, wherein a single axle is attached to each of said bow limbsthrough the respective mounting fork, and wherein each said single axlespans the respective mounting fork.
 10. A compound archery bowcomprising first and second bow limbs attached to a handle, said bowlimbs each having a single axle pin therein and wherein an eccentricallyrotatably mounted cam is mounted on the single axle pin on said secondbow limb, an anchor cable attached to an axle pin in said first bowlimb, a bowstring cable section attached to the cam, a return cablesection attached to the cam, means for rotating the cam to cause thebowstring cable section to be let off and during at least a portion ofsaid cam rotation to cause the return cable section to be let off, andwhereby the rotation of the cam causes the anchor cable to be taken upby said cam.
 11. A compound archery bow as set forth in claim 10,wherein the first and second bow limbs each have a mounting fork,wherein each of the single axle pins is attached to said bow limbsthrough the respective mounting fork, and wherein said single axle pinseach span the respective mounting fork.
 12. A compound archery bowcomprising first and second bow limbs attached to a handle, aneccentrically rotatably mounted cam mounted on one of said bow limbswith an axle pin extending through said cam, an anchor cable attachedbetween an axle pin on the one of said bow limbs opposite said cam andsaid eccentrically mounted cam, a bowstring cable and a return cableattached to said eccentrically mounted cam, whereby rotation of theeccentrically rotatably mounted cam by the bowstring cable causes thebowstring cable to be let off along an outer periphery of theeccentrically rotatably mounted cam, whereby during at least a portionof said cam rotation the return cable is let off along a path along adifferent length outer periphery of the eccentrically rotatably mountedcam, and whereby the rotation of the eccentrically rotatably mounted camby the bowstring cable causes the anchor cable to be taken up.
 13. Acompound archery bow comprising first and second bow limbs attached to ahandle, an eccentrically rotatably mounted cam defining a bowstring camand a return cable cam mounted on one of said bow limbs with an axleextending through said bowstring cam and said return cable cam, ananchor cable attached to an axle in the one of said first and second bowlimbs opposite said cam, a bowstring cable attached to said bowstringcam, a return cable attached to said return cable cam, means forrotating the cam to cause the bowstring cable to be let off and duringat least a portion of said cam rotation to cause the return cable to belet off, and whereby the rotation of the cam causes the anchor cable tobe taken up by said cam.
 14. A compound archery bow comprising first andsecond bow limbs attached to a handle, said bow limbs each having asingle axle pin therein and wherein an eccentrically rotatably mountedcam is mounted on said second limb on one of said axle pins, an anchorcable attached between the axle pin on said first limb and saideccentrically mounted cam, a second cable having a bowstring section anda return section, whereby rotation of the eccentrically rotatablymounted cam by the bowstring section causes the bowstring section to belet off and whereby during at least a portion of said cam rotation thereturn section is also let off.
 15. A compound archery bow as set forthin claim 14, whereby the rotation of the eccentrically rotatably mountedcam by the bowstring section causes the anchor cable to be taken up. 16.A compound archery bow as set forth in claim 14, wherein the first andsecond bow limbs each having a mounting fork, wherein a single axle pinis attached to each of said bow limbs through the respective mountingfork, and wherein each said single axle pin spans the respectivemounting fork.
 17. A compound archery bow comprising first and secondbow limbs attached to a handle, said bow limbs each having a single axlepin therein and wherein an eccentrically rotatably mounted cam ismounted on said second limb on one of said single axle pins, an anchorcable attached between the axle pin on said first limb and the cam, asecond cable having a bowstring section and a return section and meansfor rotating the cam to cause the bowstring section to be let off andduring at least a portion of said cam rotation to cause the returnsection to be let off.
 18. A compound archery bow as set forth in claim17, whereby the rotation of the cam causes the anchor cable to be takenup.
 19. A compound archery bow as set forth in claim 17, wherein thefirst and second bow limbs each have a mounting fork, wherein a singleaxle pin is attached to each of said bow limbs through the respectivemounting fork, and wherein each said single axle pin spans therespective mounting fork.
 20. A compound archery bow comprising firstand second bow limbs attached to a handle, said bow limbs each having amounting fork; at least one of said bow limbs having an axle pinattached therein through the respective mounting fork, said axle pinspanning the mounting fork; an eccentrically rotatable cam mounted onsaid at least one axle pin with said axle pin passing through said cam;an anchor cable attached at one end to said eccentrically mounted camand attached at an opposing end to an axle on the other of said bowlimbs; a bowstring cable section and a return cable section attached tosaid eccentrically mounted cam; wherein said cam defines a bowstringcable path and a return cable path each path including at least aportion along an outer periphery of said cam, and each path definedoutward of said axle pin; whereby rotation of the eccentricallyrotatably mounted cam by the bowstring cable causes the bowstring cablesection and the return cable section to be let off along theirrespective bowstring cable path and return cable path at least duringportions of said rotation, and whereby during at least a portion of saidrotation the anchor cable is taken up by said cam.
 21. A dual-feedsingle-cam compound bow comprising a pair of flexible resilient bowlimbs forming first and second outer bow limb ends with a handleconnecting inner ends thereof, a single drop-off cam journaled on anaxle pin at the first outer bow limb end and having eccentric peripheralgroove portions wherein each groove portion is journaled on said axlepin, a pulley concentrically journaled at the second outer bow limb endand having peripheral concentric groove portions, an elongated cablehaving an intermediate portion trained around the concentric pulley toform two cable sections extending between the pulley and the cam, onesection forming a bowstring having feed-out end portions at both endsthereof and the other section forming a take-up portion at the pulleyend thereof and a feed-out portion at the cam end thereof, both receivedin eccentric groove portions peripheral to the cam in a manner toprovide a pair of feed-out sections extending from the cam toward thepulley, the ends of the two cable sections being positively anchored tothe cam to produce the desired drop-off rotation of the cam when thebowstring is drawn, and an anchor cable extending between the two limbswith one end thereof fixed to the second bow limb end and the otheranchor cable end fixed to the cam and trained in a take-up grooveportion of the cam to produce controlled flexing of the bow limbs duringthe drawing of the bowstring.
 22. A compound bow as set forth in claim21, wherein said anchor cable has two sections at one end thereon, andwherein each such section is mounted to the second outer bow limb end onopposite sides of said pulley.
 23. A dual-feed single-cam compound bowcomprising a pair of flexible resilient bow limbs forming first andsecond outer bow limb ends with a handle connection inner ends thereof,a single drop-off cam journaled on an axle pin at the first outer bowlimb end and having eccentric peripheral groove portions wherein eachgroove portion is journaled on said axle pin, a pulley concentricallyjournaled at the second outer bow limb end and having peripheralconcentric groove portions, an elongated cable, having an intermediateportion trained around the concentric pulley to form two cable sectionsextending between the pulley and the cam, one section forming abowstring having feed-out end portions at both ends thereof and theother section forming a take-up portion at the pulley end thereof and afeed-out portion at the cam end thereof, both received in eccentricperipheral groove portions of the cam in a manner to provide a pair offeed-out sections extending from the cam toward the pulley, the ends ofthe two cable sections being positively anchored to the cam to producethe desired drop-off rotation of the cam when the bowstring is drawn,and an anchor cable extending between the two limbs with one end thereoffixed to the second bow limb end and the other anchor cable end fixed tothe cam and trained in a take-up groove portion of the cam to producecontrolled flexing of the bow limbs during the drawing of the bowstring.24. A compound bow as set forth in claim 23 wherein said anchor cablehas two sections at one end thereon, and wherein each such section ismounted to the second outer bow limb end on opposite sides of saidpulley.